The soldier died from wounds when struck by the bomb, which exploded outside a police centre and a primary school in Kirkuk on Monday, the military said.

Thirteen Iraqis, including eight schoolgirls and a toddler, were also killed in the blast when the bomber carrying food supplies exploded his vehicle.

Another 192 Iraqis were treated for injuries after the blast. The military said three more US soldiers were also wounded.

Another soldier was killed on Monday in a roadside bomb blast next to his vehicle during combat operations near Baghdad, the military said.

A third soldier and a marine were killed in combat operations in the western Anbar province on Monday, the military reported.

The latest fatalities brought the US military's losses in Iraq since the March 2003 invasion to 3,254, according to an AFP count based on Pentagon figures.

Meanwhile, nine more people have been abducted in Iraq's flashpoint province of Diyala, police said on Tuesday, a day after the bodies of 21 Shia workers snatched in similar circumstances were uncovered.

The nine workers for a provincial electrical company were kidnapped at gunpoint on their way home from work on Monday near the Shia town of Khalis, often used as a killing ground by presumed Sunni extremists.

The 21 Shias, whose bodies were found on Monday, were also kidnapped on their way back from work after gunmen ambushed their minibuses on the main road out of Baghdad to Diyala, the most dangerous area in Iraq after Baghdad.

Police in Diyala also said four insurgents were killed in Khalis on Tuesday when a car bomb they were intending to blow up detonated by accident. Two cars were gutted in the blast, police said.

Elsewhere, attacks killed three Iraqi civilians in Baghdad and three policemen in other cities, security officials said.

Two students at a pharmacy college travelling in a car through the southwestern Baghdad district of Saydiya were killed when a bomb exploded.

Another civilian was killed when a second roadside bomb exploded in the heart of the Al-Kubaisi shopping centre in Zafaraniya, in southern Baghdad.

Gunmen shot dead one policeman in an eastern district of the northern oil city of Kirkuk, another in the city of Tikrit, and a third policeman in Kut, south of Baghdad, separate police sources said.

Insurgents and sectarian killers have increasingly focused their efforts outside Baghdad where a massive US-Iraqi security crackdown, now into a seventh week, has seen American officials boast about signs of progress.